The antibiotic showdomycin and some of its analogs will be synthesized by organic chemical methods. The analogs will include various sugar analog derivatives of maleimide and maleimidyl derivatives of naturally occurring nucleosides. The compound will be screened for anticancer and antimicrobial activity. Specific enzymes from pathways of nucleic acid and carbohydrate metabolism will be used in assay procedures to determine the ability of the analogs to effect inhibition. The mechanism of inhibition and the role of the sugar will be determined. The chemical nature of the binding to amino acids will be investigated and structural details elucidated. The potential use of these compounds as active-site-directed irreversible inhibitors will be studied.